Orthodontic skeletal anchorage using a palatal external plate

Stress Analysis of Periodontal Tissue in en Masse Retraction With Integration of Maxillary Anterior Teeth: A Three-Dimensional Finite Element Method Study

OBJECTIVE

To simulate the en masse traction technique with the integration (EMTI) of six maxillary anterior teeth using a finite element model (FEM) and explore various protocols for maxillary protrusion. The study aimed to investigate root displacement and stress distribution in the periodontal ligament (PDL) by varying the retraction position and direction of EMTI applied to the maxillary anterior teeth. No actual participants were involved.

MATERIALS AND METHODS

The FEM model included six teeth (central and lateral incisors and canines) with a PDL thickness of 0.3 mm. The model encompassing the alveolar bone (ALB) and EMTI had 180,528 elements and 47,836 nodes. The EMTI integrated six anterior teeth via a 0.9-mm-diameter stainless steel lingual wire, equipped with three moment arms extending toward the root apex: one midline (central arm) and two distal to the canines (lateral arms). The position and direction of the traction force applied to the three moment arms of the EMTI were varied to assess crown and apex displacement, as well as PDL stress.

RESULTS

Lingual tipping was consistent across all protocols, emphasizing controlled incisor tipping. The application of horizontal traction at 10 mm and traction at 7 mm from the central and lateral arms of the EMTI, respectively, demonstrated the most uniform stress distribution across the PDL of all six anterior teeth.

CONCLUSIONS AND CLINICAL SIGNIFICANCE

The FEM analysis results suggest that the new EMTI method, which retracts the maxillary anterior teeth as a unit, is effective for tooth movement and PDL stress distribution. The EMTI technique, with its specific traction protocols and emphasis on controlled tipping, appears to be a promising approach for addressing maxillary protrusions.

Severe Maxillary Protrusion Treated with Surgically Assisted Rapid Maxillary Expansion

In this case, surgically assisted rapid maxillary expansion (SARME) was successfully adopted to treat a skeletal maxillary protrusion with large overjet and severe crowding. The female patient, aged 25 years and 11 months, was diagnosed with skeletal maxillary protrusion with severe crowding and excessive overjet associated with labially inclined maxillary central incisors. After achieving sufficient space for surgical incision between bilateral maxillary central incisors, the SARME was performed. A total of 8.0 mm lateral expansion of the maxilla was completed. At 48 days after surgery, the Hyrax appliance was replaced with an Anchor-Lock system used as an external surgical stent and skeletal anchorage for maxillary group distalization, and the distal movement of the maxillary molars was initiated without waiting for bone healing of the separated midpalatal suture by SARME. Twenty-five months' treatment, including surgical preparation, achieved an acceptable and stable occlusion with adequate interincisal relationship. The occlusion was much more stable with a little relapse through more than 4 years' retention period. In conclusion, SARME followed by the Anchor-Lock system might lead to favorable occlusal outcome in the long term without any relapses.

Clinical crown height changes in adult patients after non-extraction, orthodontic treatment: a retrospective cohort study

OBJECTIVE

To assess changes in clinical crown height (CCH) in adult orthodontic patients treated by fixed appliances to distalise the molars.

DESIGN

Retrospective case series study.

SETTING AND PATIENTS

A total of 30 adults with healthy periodontal tissues who received orthodontic treatment at the Department of Orthodontics, Yokohama, Japan and its related orthodontic clinic were assessed.

METHODS

CCH was measured as the distance from the gingival margin to the crown plane perpendicular to the tooth axis. Treatment changes of CCH of each tooth were examined on the labial/buccal and lingual/palatal side.

RESULTS

In the upper dentition, on the labial/buccal side, the CCH of the lateral incisors, canines, first premolars, first molars and second molars were increased significantly (P < 0.01), with a median value of 0.41 mm, 0.43 mm, 0.28 mm, 0.43 mm and 0.55 mm, respectively. In contrast on the palatal side, the CCH of the central incisors, first molars, and second molars decreased significantly (P < 0.01), with a median value of -0.41 mm, -0.30 mm and -0.20 mm, respectively. In the lower dentition on the labial/buccal side, the CCH of the first premolars, second premolars and first molars were increased significantly, with a median value of 0.39 mm (P < 0.01), 0.43 mm (P < 0.01) and 0.19 mm (P < 0.05), respectively. The second molars exhibited a significant decrease in CCH with a median value of -0.26 mm (P < 0.05). On the lingual side, the CCH of the central incisors, lateral incisors, canines, first premolars, second premolars and first molars were increased significantly (P < 0.01), with a median value of 0.28 mm, 0.22 mm, 0.31 mm, 0.37 mm, 0.26 mm and 0.28 mm, respectively.

CONCLUSION

Significant differences were observed in CCH before and after treatment for many teeth, the average change was less than 0.5 mm. The impact on the long-term health of the periodontal tissue is unknown.

Skeletal and dentoalveolar changes after total maxillary arch distalization using the casted palatal plate vs. buccal miniscrews: A randomized clinical trial

OBJECTIVES

To evaluate treatment changes after total maxillary arch distalization using the casted palatal plate compared with buccal miniscrews.

MATERIAL AND METHODS

This was a randomized, parallel, two-arm, single center trial. Participants were young adults with class II dental relationships and normal or horizontal growth patterns. The patients were treated with total distalization of the maxillary arch and were randomly allocated, according to the anchorage devices, between the plate group and the minivis group. The primary outcomes were sagittal, vertical and angular changes of molars and incisors, while the secondary outcomes were skeletal and soft tissue changes. Outcomes were evaluated on lateral cephalograms and blinding of outcome assessment was implemented. A multivariate analysis of Variance (MANOVA) tests were used and Bonferroni correction for multiple comparisons with P<0.001.

RESULTS

Forty patients (33 females and 7 males; mean age 20±3.1 years) where enrolled. A significant distalization of U6 was observed in both groups (4.33mm in the plate group and 1.88mm in the miniscrews group). It was combined with significant intrusion and non-significant distal tipping of the U6 in the plate group (1.85mm and 3.10°, respectively), while intrusion and distal tipping were non-significant in the miniscrew group (0.8mm and 2°, respectively). Both groups showed significant retraction and palatal inclination without vertical changes of U1. Only the plate group produced significant reduction of ANB and Wits. Upper and lower lips were retracted and the nasolabial angle increased significantly in both groups. There was no significant main effect of the appliance type on the comparison of treatment effects between the two groups (P=0.623). However, univariate comparisons showed that the plaque group showed greater distalization of the U6 (P<0.001).

CONCLUSIONS

Both the casted palatal plate and buccal miniscrews can be viable devices for total distalization of the maxillary arch in the treatment of class II patients. The casted plate may be considered when more extensive distalization is required.

[The use of an individualized mini plate for the distalization of teeth]

The case of treatment of a 32-year-old patient with complaints about the aesthetics of a smile and the absence of teeth 17 and 46 is presented. During the examination, it was established: the retraction position of the teeth in the frontal part of the upper jaw, the closure of the molars according to the II class of the second subclass of Engl (distal bite), the vestibular position of the teeth 13, 23. To change the spatial position of the lower jaw, the fixation of the bracket system on the upper jaw was performed. and also an individualized mini-plate was installed in the area of the zygomatic alveolar ridge on the right and left, for distalization of the dentition of the upper jaw with the help of orthodontic traction applied from the teeth to the mini-plates. This clinical example demonstrates the possibility of using individualized mini-plates for distalization of the upper dentition, as an alternative and more stable method of treatment in such clinical cases.

Efficiency of maxillary total arch distalization using temporary anchorage devices (TADs) for treatment of Class II-malocclusions: A systematic review and meta-analysis

OBJECTIVES

To evaluate the treatment effects and post-treatment stability of the maxillary total arch distalization using TADs during the non-extraction treatment of class II malocclusions.

MATERIALS AND METHODS

Study involved an electronic search followed by hand searching for randomized and non-randomized clinical studies about maxillary total arch distalization using TADs. After data extraction and risk of bias assessment, meta-analysis was performed for dental, skeletal and soft tissue changes using the Generic-inverse variance approach by use of the mean difference and random-effect model.

RESULTS

In total, 1788 articles were identified, 88 full texts were screened and 22 studies were found eligible; 17 of them were included in the quantitative analysis. The means of distalization/distal tipping of the maxillary first molar were 4mm/3.17° in adults, 3.95mm/1.61° in adolescents after treatment with the Modified C-Palatal plate (MCPP), while they were 2.44mm/2.91° with the inter-radicular mini-screws. Both MCPP's treatment in adults and inter-radicular mini-screws resulted in significant intrusion of U6 (1.64 and 0.75mm, respectively), while insignificant extrusion of U6 was resulted in adolescents treated by MCPP. MCPP appliances resulted in palatal inclination/extrusion of maxillary incisors U1 (6.77°/2mm in adults, 7.46°/3.14mm in adolescents). In contrast, inter-radicular mini-screws resulted in less palatal less amount of palatal inclination/insignificant intrusion of U1 (2.42°/0.14mm). MCPP treatment also resulted in significant changes in the skeletal measurements (SNA, ANB, occlusal and mandibular planes). Insignificant differences were found between subgroups in the retraction amount of maxillary incisors, as well as the upper and lower lips. In the follow-up of adolescents treated with MCPP, a significant amount of mesial movement, mesial tipping, and extrusion (2.94mm, 2.84°, and 3.94mm, respectively) was found. However, skeletal and occlusal corrections of the Class II relationship were maintained.

CONCLUSIONS

Maxillary total arch distalization using TADs can be an effective and stable treatment procedure. However, RCTs or prospective cohort studies are highly recommended to establish a clinical evidence regarding their efficiency.

A comparison of treatment effects of total arch distalization using modified C-palatal plate vs buccal miniscrews

OBJECTIVE

The purpose of this study was to compare the treatment effects of palatally vs buccally placed temporary anchorage devices.

MATERIALS AND METHODS

Of 40 Class II division 1 malocclusion patients, 22 were treated with modified C-palatal plate (MCPP) appliances (age 21.9 ± 6.6 years), and 18 (age 24.2 ± 6.8 years) were treated with buccally placed miniscrews between the maxillary first molar and second premolar. A total of 26 linear and angular measurements were analyzed on pre- and posttreatment lateral cephalograms. Multivariate analysis of variance was performed to evaluate the treatment effects within each group and to compare the effects between groups.

RESULTS

Overall, the MCPP appliances showed 4.2 mm of distalization, 1.6 mm of intrusion of the first molar with 2° tipping, and 0.8 mm extrusion of incisors. The miniscrew group resulted in 2.0 mm of distalization, 0.1 mm intrusion of the first molar with 7.2° tipping, and 0.3 mm of incisor extrusion. Regarding soft tissue change, in the MCPP group, the upper lip was significantly retracted ( P < .001).

CONCLUSIONS

Comparing the treatment effects between MCPP appliances and buccal miniscrews, the MCPP appliances showed greater distalization and intrusion with less distal tipping of the first molar and less extrusion of the incisor compared to the buccal miniscrews.